KF/ZrO2/Fe3O4 magnetic solid base catalyst was prepared by impregnation method, which loading alkali source KF on composite magnetic carrier ZrO2/Fe3O4. Its structure and properties were characterized by scanning transmission electron microscope, specific surface test and the determination of base strength and alkali content; its catalytic effect was also evaluated according to the synthesis of polyglycerol. The results showed that this magnetic solid base catalyst belongs to solid strong base with KF alkaline center in the surface, pH between 11.1~15.0 and total alkali 0.2 mmol/g. During synthesis of polyglycerol, the catalyst shows good catalytic performance such as mild reaction condition, moderate polymerization degree, products with light color, easily separate product from the catalysis, which indicates high application value and economic value.